Bacterial diversity and species concept Flashcards
1
Q
“Housekeeping” functions
A
- cell structure
- replication, transcription, translation
- metabolism
2
Q
“Accessory/supplementary” functions
A
- virulence
- antibiotic resistance
- metabolism - rare substrates
3
Q
Genomes vs. Environment
A
selection acts to increase a species fitness for its environment
4
Q
Genome changes
A
- point mutation SNPs, frame shifts
- acquisition
- deletion
- rearrangement
5
Q
Bacterial diversity: mechanisms and examples
A
- point mutation
- acquisition
- deletions
6
Q
Bacterial diversity: point mutation
- example
A
Myobacterium tuberculosis
- mutation rate 10-6 to 10-9
- Rifampicin resistance
- targets a sub-unit of RNA polymerase
- nt substitutions in rpoB gene
7
Q
Rifampicin
A
targets a sub-unit of RNA polymerase
8
Q
Acquisition
A
- DNA movement between cells
- DNA movement within cells
9
Q
DNA movement between cells
A
- transformation
- bacteriophage
- plasmids
10
Q
DNA movement within cells
A
- transposable elements
11
Q
transformation
A
uptake of free DNA from environment DNA recombined into genome cell acquires new gene(s)
12
Q
bacteriophage
A
can move genes between strains/species harbour accessory functions transduction - phage aberrantly transports non-phage DNA -> bacterial DNA transferred to new cell
13
Q
plasmids
A
extra-chromosomal DNA
can encode ‘accessory’ functions
e.g.) antibiotic resistance - salmonella outbreak
14
Q
transposons
A
DNA element >10kb in size
Transposition function - one DNA location to another WITHIN a cell
accessory functions
e.g.) Trimethoprin res. - synthetic antibiotic
15
Q
deletions
A
intra-cellular event scale delection - bt, codons, genes, chromosomal segments various mechanisms - e.g.) recombination -> 2 homologous sequences -> same orientation
